One proposed structure of a power output apparatus mounted on a vehicle has an internal combustion engine, a planetary gear unit that has a carrier and a ring gear respectively linked to an output shaft of the internal combustion engine and to an axle of the vehicle, a first motor that outputs power to a sun gear of the planetary gear unit, and a second motor that outputs power to the ring gear (see, for example, Patent Document 1). When the temperature of a catalyst in a catalytic converter used for exhaust emission control of the internal combustion engine increases or exceeds a preset reference temperature, this prior art power output apparatus prohibits cutoff of fuel to the internal combustion engine, with the view to restricting deterioration of the catalyst. In response to the driver's requirement for a braking force in prohibition of the fuel cutoff, this power output apparatus regulates a throttle opening to set an output torque of the internal combustion engine equal to 0, controls the operation of the first motor to keep the rotation speed of the internal combustion engine unchanged, and performs regenerative control of the second motor to output the required braking force.
Patent Document 1: Japanese Patent Laid-Open No. 2004-340102